Wintershall struggles to boost output from Norway's Maria field

OSLO (Reuters) - German oil firm Wintershall's flagship project in Norway - the Maria oil and gas field - is not meeting output expectations due to water injection issues, the company said on Monday.

The field, which started nine months ahead of schedule at end-2017, was welcomed by the Norwegian government as an innovative project to squeeze more barrels from Norway's continental shelf.

But 10 months after the startup Maria's output has not lived up to expectations.

"The production performance of the Maria field does not yet fully meet our expectations," Wintershall said in an email to Reuters. The company did not give details of these expectations.

Winters said the reason for this could be a limitation in the connectivity between the water injection and oil production layers in the reservoir.

"Some testing and investigations will be performed to obtain more information and to define the way forward," Wintershall said in the email.

The company, which injects water to keep the pressure in the reservoir some 3,800 metres deep, said it was too early to say whether it would have to revise estimates for the field's recoverable reserves, which currently stand at around 180 million barrels of oil equivalents.

Spirit Energy, which has a 20 percent stake in the field, said on its website that at peak production Maria was expected to add about 8,300 barrels of oil equivalents (boed) net to Spirit Energy's output.

That would put Maria's expected gross peak production at more than 41,500 boed, according to Reuters' calculations.

The latest data from the Norwegian Petroleum Directorate showed the Maria field produced 23,400 barrels of oil equivalents per day (boed) in July.

Wintershall has 50 percent stake in Maria's licence, and Norway's state-owned Petoro holds the remaining 30 percent.

Norwegian business Dagens Naeringsliv was the first to report the issues at the Maria field.

Wintershall, owned by German chemicals group BASF <BASFn.DE>, is in the process of merging with oil and gas firm DEA.

Spirit Energy is 69 percent owned by Britain's Centrica <CEN.L>.

(Reporting by Nerijus Adomaitis. Editing by Jane Merriman)